Bathmate works and works very well when used to aide in your manual PE. There are lots of guys here that have used it to great success - browse through the threads to pick up on some tips and see what they've done.
Personally, I love the thing - I generally use it in the mornings and also after I use my dry pump (when I can). The pressure feels great and the stretches you can do with it are pretty damn intense.
I agree - it really helps flaccid hang. I pump nearly every morning in the shower (over the past week or so since I got my new one) and it keeps me long and plump for a good portion of the day.
This is my experience as well.
I think Bathmate can be part of a routine and is helpful. It provides what I call "stretching in 3D". And stretching is stretching = growth = gains! But because the stretch is very limited, the gains would come very slow if you were just using it by itself.